Malaria is a devastating disease that causes significant mortality in many countries of the developing world. The most deadly form of the disease is caused by the opportunistic pathogen, Plasmodium falciparum. Significant efforts have been made to understand the process by which the parasite invades a host cell to establish infection, yet relatively little is known about the process by which the parasite mediates its release after replication has occurred. This process is essential for propagation of the pathogen and agents that block rupture are likely to be valuable for development as novel anti-malarial agents. This proposal outlines plans to use small molecules to study the functional roles of proteases that regulate the process of host cell rupture. Specifically, it describes the use of phenotypic screens using libraries of protease inhibitors to identify compounds that block the release of parasites from host red blood cells. Screening hits will be used to identify protease targets and to dissect the details of their regulation of host cell rupture. Finally, lead compounds will be applied to mouse models of malaria to validate multiple proteases as drug targets for novel anti-malarial therapies.